Dave Jiang <[email protected]> wrote:
> Add support for setting and/or updating passphrase on the Intel nvdimms.
> The passphrase is pulled from userspace through the kernel key management.
> We trigger the update via writing "update" to the sysfs attribute
> "security". The state of the security can also be read via the "security"
> attribute. libnvdimm will generically support the key_change API call.
Btw, could you use a logon-type key rather than spinning your own? Do you
specifically not want it to be updateable?
> +static int intel_dimm_security_update_passphrase(
> + struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
> + struct nvdimm_key_data *old_data,
> + struct nvdimm_key_data *new_data)
You might want to mark old_data and new_data as const here. At least, they
don't appear to be changed. Also, can you stick a banner comment on the
function to say what it actually does? Is it changing the key stored in h/w
or is it meant to be changing what's stored in the key payload?
> + /* request new key from userspace */
> + key = nvdimm_request_key(dev);
> + if (!key) {
> + dev_dbg(dev, "%s: failed to acquire new key\n", __func__);
> + return -ENXIO;
> + }
> +
> + dev_dbg(dev, "%s: new key: %#x\n", __func__, key->serial);
> +
> + if (key->datalen == NVDIMM_PASSPHRASE_LEN) {
> + old_data = NULL;
> + new_data = key->payload.data[0];
> + } else if (key->datalen == (NVDIMM_PASSPHRASE_LEN * 2)) {
> + new_data = key->payload.data[0];
> + old_data = new_data + NVDIMM_PASSPHRASE_LEN;
> + } else {
> + key_invalidate(key);
> + key_put(key);
> + dev_warn(dev, "Incorrect key payload size for update: %u\n",
> + key->datalen);
> + return -EINVAL;
> + }
> +
> + down_read(&key->sem);
> + rc = nvdimm->security_ops->change_key(nvdimm_bus, nvdimm, old_data,
> + new_data);
Why do you need to get a read lock on key->sem and not a write-lock?
> + if (rc == 0 && key->datalen == (NVDIMM_PASSPHRASE_LEN * 2))
> + memcpy(old_data, new_data, NVDIMM_PASSPHRASE_LEN);
You appear to be changing the key content here. If that's the case, don't you
need to write-lock key->sem?
> + up_read(&key->sem);
David
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